IB Chemistry 1998 HL Question?

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2017-11-05 9:47 pm

A nickel catalyst was placed in a 1 decimeter cubed flask containing a mixture of 800 centimeters cubed of hydrogen and 200 centimeters cubed of ethene at 0 degrees Celsius and 1.0 atmosphere. The mixture was heated to 150 degrees Celsius for 24 hours and cooled to 0 degrees Celsius again. Assuming that all ethene was converted to ethane, what is the final pressure in the flask?

回答 (1)

戇戇居士

2017-11-05 10:14 pm

✔ 最佳答案

After mixing the two gases :
Partial pressure of C₂H₄ (ethene) = (1.0 atm) × [(200 cm³)/(1000 cm³)] = 0.20 atm
Partial pressure of H₂ (hydrogen) = (1.0 atm) × [(800 cm³)/(1000 cm³)] = 0.80 atm

Balanced equation for the reaction :
C₂H₄(g) + H₂(g) → C₂H₆(g)
Mole ratio C₂H₄ : H₂ : C₂H₆ = 1 : 1 : 1
0.20 atm of C₂H₄ completely reacts.

After reaction :
Partial pressure of C₂H₄ = 0 atm
Partial pressure of H₂ = (0.80 - 0.20) atm = 0.60 atm
Partial pressure of C₂H₆ (ethane) = 0.20 atm

Final pressure = (0 + 0.60 + 0.20) atm = 0.80 atm

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